Rail mountable diopter rear sights are desirable for their ability to provide an optimum sighting system for both close quarters battle and medium to long range engagements. Close Quarters Battle (CQB) is a type of fighting in which small units engage the enemy with personal weapons at very short range, potentially to the point of hand-to-hand combat. CQB is defined as a short-duration, high-intensity conflict, characterized by sudden violence at close range.
In contrast, medium to long-range engagements are typically lower intensity and require accurate sighting of objects at greater distances. In these circumstances, the downward acceleration on the projectile imparted by gravity is of greater significance. The effect of gravity on a projectile in flight is often referred to as bullet drop because it causes the bullet to drop from the shooter's line of sight. For accuracy at longer distances, the sighting components of a gun must compensate for the effect of bullet drop.
To accommodate such users, rotating four position drum sights have been developed wherein an aperture is present at each position. The height of the apertures is calibrated to compensate for bullet drop at particular distances, such as 100-400 m. However, many of these devices suffer from the need for a locating screw to calibrate the drum sights' elevation that is separate from the pin that enables rotation of the drum sights. Furthermore, a separate tool is typically required to adjust the locating screw, and such a tool may not be available in the field. In addition, the calibration screw systems traditionally employed are complex, with small moving parts that are subject to damage and improper adjustment under harsh field conditions.
Therefore, a need exists for a new and improved rail mountable diopter rear sight that provides an optimum sighting system for both close quarters battle and medium to long-range engagements. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the rail mountable diopter rear sight according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of providing an optimum sighting system for both close quarters battle and medium to long-range engagements.